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| United States Patent |
5,516,811
|
|
Bartlett
, et al.
|
May 14, 1996
|
Polymer foams containing blocking agents
Abstract
An improved closed-cell polymer foam involves the use of a polyfluorocarbon
forming agent (e.g., HCFC-22) in combination with an effective amount of a
hydrogen bond forming blocking agent (e.g., organic ether, ester or
ketone). The presence of the blocking agent is shown to significantly
reduce the escape of blowing agent from and entry of air into the foam
resulting in low thermal conductivity over a longer period of time and
improved thermal insulation value.
| Inventors:
|
Bartlett; Philip L. (Wilmington, DE);
Creazzo; Joseph A. (Wilmington, DE);
Hammel; Howard S. (Bear, DE)
|
| Assignee:
|
E. I. Du Pont de Nemours and Company (Wilmington, DE)
|
| Appl. No.:
|
427643 |
| Filed:
|
April 24, 1995 |
| Current U.S. Class: |
521/131; 521/155 |
| Intern'l Class: |
C08J 009/02; C08G 018/00; C08L 025/06; C08L 075/04 |
| Field of Search: |
521/131,155
|
References Cited
U.S. Patent Documents
| 3222304 | Dec., 1965 | Ingram.
| |
| 3671470 | Jun., 1972 | Case | 521/159.
|
| 4789690 | Dec., 1988 | Milovanovic-Lerik et al. | 521/137.
|
| 4972002 | Nov., 1990 | Volkert | 521/120.
|
| 4972003 | Nov., 1990 | Grunbauer et al. | 521/131.
|
| 4997706 | Mar., 1991 | Smits et al. | 428/364.
|
| Foreign Patent Documents |
| 0001791 | Oct., 1977 | EP.
| |
| 0024324 | Aug., 1979 | EP.
| |
| 0305084 | Mar., 1989 | EP.
| |
| 88849 | Oct., 1965 | FR.
| |
| 60-110733 | Jun., 1985 | JP.
| |
Other References
Bartlett; Polyurethane Foam Blowing Agents, 430, Research Disclosure, Jul.
1987.
|
Primary Examiner: Seidleck; James J.
Assistant Examiner: Cooney, Jr.; John M.
Attorney, Agent or Firm: Boyer; Michael K.
Parent Case Text
RELATED APPLICATION DATA
This is a continuation of application Ser. No. 07/702,282 filed Jun. 28,
1991, now abandoned, which is a continuation of 07/577,045 filed on Aug.
28, 1990 now abandoned, which is a continuation of 07/500,051 filed on
Mar. 23, 1990, now abandoned.
Claims
We claim:
1. A method of manufacturing a closed cell foam comprising the steps of:
(a) admixing an effective amount of a hydrogen-containing halocarbon
blowing agent to the B-side component of a polyurethane or
polyisocyanurate foam such as to hydrogen bond said halocarbon with a
polyol in said B-side component, said halocarbon is selected from the
group consisting of: CH.sub.2 F.sub.2 ; CHF.sub.2 CF.sub.3 ; CHF.sub.2
CHF.sub.2 ; CH.sub.2 FCF.sub.3 and mixtures thereof,
(b) contacting said admixture of step (a) with an effective amount of an
A-side component of a polyurethane or polyisocyanurate foam for sufficient
time and temperature to produce foaming; and
(c) recovering a fine closed-cell structured foam exhibiting improved
k-factor relative to that predicted from VTC data.
2. A method of claim 1 further comprising admixing a second blowing agent
gas to said B-side wherein said second blowing agent gas is selected from
the group consisting of:
CH.sub.2 FCH.sub.2 F; CH.sub.3 CF.sub.3 ; CHF.sub.2 CH.sub.3 ; CO.sub.2 ;
N.sub.2 ; C.sub.3 to C.sub.6 hydrocarbons and mixtures thereof.
3. A method of claim 1 wherein said hydrogen-containing halocarbon blowing
agent is 1,1,1,2-tetrafluoroethane.
4. A method of claim 1 wherein said hydrogen-containing halocarbon blowing
agent is 1,1,1,2-tetrafluoroethane and water is added to produce, in situ,
CO.sub.2 as a second blowing agent.
5. A method of manufacturing a closed cell foam comprising the steps of:
(a) admixing an effective amount of 1,1,1,2-tetrafluoroethane blowing agent
to the B-side component of a polyurethane or polyisocyanurate foam such as
to hydrogen bond said 1,1,1,2-tetrafluoroethane with the polyol in said
B-side component;
(b) contacting said admixture of step (a) with an effective amount of an
A-side component of a polyurethane or polyisocyanurate foam for sufficient
time and temperature to produce foaming; and
(c) recovering a fine closed-cell structured foam exhibiting improved
k-factor relative to that predicted from VTC data.
6. A method of claim 5 wherein said B-side component admixed with an
effective amount of 1,1,1,2-tetrafluoroethane blowing agent further
comprises an effective amount of water to produce, in situ, CO.sub.2 as a
second blowing agent.
7. A closed-cell rigid polymer foam prepared from a foam-forming
composition containing a physical blowing agent present from about 5 up to
about 30 weight percent based on the total weight of the composition, and
characterized in that the physical blowing agent comprises a
hydrogen-bonding C.sub.1 -C.sub.2 polyfluorocarbon compound containing no
chlorine or bromine atoms.
8. The foam of claim 7 wherein the polyfluoroearbon compound containing no
chlorine or bromine atoms is one or more selected from the group
consisting of 1,1,1,2-tetrafluoroethane, 1,2,2-tetrafluoroethane and
pentafluoroethane.
9. The foam of claim 8 wherein the polyfluorocarbon compound is
1,1,1,2-tetrafluoroethane.
10. A process for producing a closed-cell rigid polyurethane or
polyisocyanurate polymer foam containing within its cells a gas mixture
comprising a hydrogen bonding C.sub.1 -C.sub.2 polyfluorocarbon compound
containing no chlorine or bromine atoms characterized in that
(a) an isocyanate-containing compound is mixed and allowed to react with an
active hydrogen-containing compound in the presence of from about 5 to
about 30 weight percent, based on combined weight of isocyanate-containing
compound, of a physical blowing agent comprising the polyfluorocarbon
compound.
11. A closed-cell rigid polymer foam prepared from a foam-forming
composition containing a physical blowing agent present in up to about 20
weight percent based on the total weight of the composition, and
characterized in that the physical blowing agent comprises a
hydrogen-bonding C.sub.1 -C.sub.2 polyfluorocarbon compound containing no
chlorine or bromine atoms.
12. The foam of claim 7 or 11 wherein said compound comprises
pentafluoroethane.
13. The foam of claim 7 or 11 wherein said compound comprises
difluoromethane.
14. The foam of claim 7 or 11 wherein said compound comprises
1,1,2,2-tetrafluoroethane.
15. The foam of claim 7 or 11 wherein said compound comprises
1,1,1,2-tetrafluoroethane.
16. The foam of claim 7 or 11 wherein said physical blowing agent further
comprises a non-hydrogen bonding hydrofluorocarbon.
17. The foam of claim 7 or 11 wherein said foam comprises thermoset foam.
18. The foam of claim 7 or 11 wherein said foam comprises a thermoplastic
foam.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to improved polymer foams and foaming agents by the
use of blocking agents. More specifically, the invention relates to
combinations of a hydrogen bond forming blocking agent and a
hydrogen-containing halocarbon and a method of using the same in closed
cell polymer foams to reduce permeation of air and/or hydrohalocarbon,
thereby maintaining low thermal conductivity and improved thermal
insulation value of the foam.
2. Description of Related Art, including Information Disclosed under
.sctn..sctn.1.97-1.99
It is generally known and an accepted commercial practice to add a blowing
agent to various polymeric materials during fabrication such as to produce
a cellular (expanded foam) material. Typically, the blowing agent can be
either a reactive solid or liquid that evolves a gas, a liquid that
vaporizes, or a compressed gas that expands during final fabrication
producing the desired polymeric foam. Such foams are categorically either
closed cell (i.e., non-porous, continuous polymer phase with discontinuous
gas phase dispersed therein) or open cell (porous) foams which are
advantageously employed in various end use applications and exhibit
various advantages associated with the particular type of foam produced.
In describing the closed cell foam as involving a discontinuous gas phase,
it should be appreciated that this description is an over simplification.
In reality the gas phase is dissolved in the polymer phase and there will
be a finite substantial presence of gas (blowing agent) in the polymer.
Furthermore and as generally known in the art, the cell gas composition of
the foam at the moment of manufacture does not necessarily correspond to
the equilibrium gas composition after aging or sustained use. Thus, the
gas in a closed cell foam frequently exhibits compositional changes as the
foam ages leading to such known phenomenon as increase in thermal
conductivity or loss of insulation value.
Closed cell foams are usually employed for their reduced thermal
conductivity or improved thermal insulation properties. Historically,
insulating polyurethane and polyisocyanurate foams have been made using
trichlorofluoromethane, CCl.sub.3 F (CFC-11), as the blowing agent.
Similarly, insulating phenolic foam is known to be made from
phenol-formaldehyde resins (typically via an intermediate resole mixture
involving a phenol-formaldehyde oligomer condensate) using blends of
1,1,2-trichlorotrifluoroethane, CCl.sub.2 FCClF.sub.2 (CFC-113), and
CFC-11 as the blowing agent. Also, insulating thermoplastic foam such as
polystyrene foam is commonly manufactured using dichlorodifluoromethane,
CCl.sub.2 F.sub.2 (CFC-12), as the blowing agent.
The use of a chlorofluorocarbon as the preferred commercial expansion or
blowing agent in insulating foam applications is in part based on the
resulting k-factor (i.e., the rate of transfer of heat energy by
conduction through one square foot of one inch thick homogenous material
in one hour where there is a difference of one degree Fahrenheit
perpendicularly across the two surfaces of the material) associated with
the foam produced. Thus, it is generally known and accepted that a
chlorofluorocarbon gaseous phase within the closed cell is a superior
thermal barrier relative to other inexpensive gases such as air or carbon
dioxide. Conversely, the natural intrusion of air into the foam over time
and to a lesser extent the escape of the chlorofluorocarbon from the cell
is deleterious to the desired low thermal conductivity and high insulative
value of the foams. Also, the escape of certain chlorofluorocarbons to the
atmosphere is now recognized as potentially contributing to the depletion
of the stratospheric ozone layer and contributing to the global warming
phenomenon. In view of the environmental concerns with respect to the
presently used chlorofluorocarbon blowing agents, it is now generally
accepted that it would be more desirable to use hydrochlorofluorocarbons
or hydrofluorocarbons rather than the chlorofluorocarbons. Consequently,
the need for a method or way of inhibiting the permeation of air and
blowing agent through the polymer phase of the polymeric foam exists and
hopefully any such solution to the problem would be effective in
inhibiting the permeation of the proposed alternative halocarbons.
Historically, various methods and compositions have been proposed, with
varying degree of success, to alleviate and/or control problems associated
with permeation of gases into and out of polymeric foams. For example, in
U.S. Pat. No. 4,663,361 the problem of shrinkage (lack of dimensional
stability) associated with using any blowing agent other than
1,2-dichlorotetrafluoroethane in the manufacture of foamed polyethylene is
addressed. In this reference, a stability control agent is used in either
a homopolymer or copolymer of ethylene wherein the blowing agent is
isobutane or isobutane mixed with another hydrocarbon or a chlorocarbon,
fluorocarbon or chlorofluorocarbon. The stability control agent is either
partial esters of long chain fatty acids with polyols, higher alkyl
amines, fatty acid amides, olefinically unsaturated carboxylic acid
copolymers, or polystyrene. This reference also describes other prior art
and is included by reference for such purpose.
In U.S. Pat. No. 4,243,717 a Fischer-Tropsch wax is added to expanded
polystyrene beads to produce a stable cell structure in the foam, without
specific reference to the permeation of blowing agent or air. In Canadian
Patent 990,900 the use of a barrier material or blocking agent is
disclosed to alleviate the problem of gas migration through the cell wall
specifically at the time of foaming. The particular problem addressed in
this Canadian patent is the rupture and total collapse of the cell walls
that frequently occur in the manufacture of closed cell polyethylene foam.
This problem is attributed to the fact that the cell walls for such foams
are permeable to the rapidly expanding gas under the influence of the heat
liberated by the exothermic polymer crystallization. The specific solution
disclosed in this reference is to use a blend of polyethylene and
polypropylene along with a barrier resin such as an elastomer containing
polystyrene or acrylic resin which are intended to contribute high melt
strength to the cell wall at the foaming temperature. An inert nucleant is
also employed along with at least two gaseous propellants of substantially
different vapor pressures.
In U.S. Pat. No. 4,795,763 the use of at least 2 percent carbon black as a
filler uniformly dispersed in a polymeric foam is shown to reduce the aged
k-factor of the foam to below the aged k-factor of the corresponding
unfilled foam.
SUMMARY OF THE INVENTION
The present invention provides a method of preventing or slowing down both
the rate of intrusion or permeation of air into the closed cells of a
polymeric foam as well as preventing or slowing down the escape of the
blowing agent by permeation or migration out of the polymer foam cells.
Thus, according to the present invention the effective rate of permeation
of air and/or hydrohalocarbon across the polymeric phase of the foam is
substantially reduced by virtue of the presence of a blocking agent.
Further according to the present invention a blocking agent capable of
hydrogen bond formation with the hydrogen-containing halocarbon is
incorporated into the polymeric foam and thus tends to form hydrogen bonds
with the blowing agent. This in turn dramatically reduces the permeation
rate of the hydrogen-containing blowing agent retaining it in the foam.
The presence of the blocking agent also functions to reduce entry of air
into the polymer foam. By reducing the entry of air into insulating foam
and simultaneously reducing the permeation of blowing agents out of
insulating foam, the blocking agents according to the present invention
produce foams which better maintain their insulating characteristics
relative to foams made without these hydrogen bond forming agents.
Thus, the present invention provides in a closed cell thermoplastic or
thermoset polymer foam characterized by a continuous polymeric phase and a
discontinuous gaseous phase, the improvement comprising: (a) a gaseous
phase comprising at least one hydrogen-containing halocarbon; and (b) an
effective amount of a hydrogen bond forming blocking agent. Preferably the
hydrogen bond forming blocking agent is an organic ether, ester or ketone
and is preferably present in the range of from about 0.1 to about 20
weight percent based on the total weight of foam.
Since the blocking agent according to the present invention can often be
conveniently incorporated, marketed and used in combination with the
blowing agent, the present invention further provides an improved
thermoplastic or thermoset polymer foaming composition comprising:
(a) a hydrogen-containing halocarbon; and
(b) an effective amount of a hydrogen bond forming blocking agent.
The improved method according to the present invention involves, in a
method of manufacturing an expanded polymeric foam wherein a blowing agent
expands as the polymeric phase solidifies, the specific improvement
comprising the steps of:
(a) selecting a hydrogen-containing halocarbon as the blowing agent; and
(b) adding an effective amount a hydrogen bond forming blocking agent to
reduce the permeation of air into the foam or slow down the escape of
blowing agent from of the foam.
It is an object of the present invention to provide a blocking agent that
when incorporated into a polymeric foam will reduce or prevent the
intrusion of air into the foam and/or the permeation or escape of blowing
agent from the foam. It is a further object of the present invention to
provide such a blocking agent that is particularly useful with the
hydrogen-containing chlorofluorocarbons and hydrogen-containing
fluorocarbons (i.e., the HCFCs and HFCs) in that the blocking agent will
hydrogen bond with the hydrohalomethanes and hydrohaloethanes, thus
significantly reducing their rate of permeation and escape from a closed
cell polymeric foam. It is an associated object of the present invention
to provide insulating foam containing a blocking agent and a method of
manufacturing the same that exhibits preservation of the insulating
properties over longer periods of times relative to the absence of the
blocking agent. Fulfillment of these objects and the presence and
fulfillment of additional objects will be apparent upon complete reading
of the specification and the claims.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Polymer foams typically involve a continuous or at least a contiguous phase
in a cellular structure. This cellular structure can be either flexible or
rigid and is categorically either an open cell structure (i.e., the
individual cells are ruptured or open producing a soft, porous "sponge"
foam which contains no blowing agent gas) or a closed cell structure
(i.e., the individual cells contain blowing agent gas surrounded by
polymeric sidewalls with minimum cell-to-cell gas flow). Thermally
insulating foams are closed cell structures containing a blowing agent gas
(i.e., a gas formed in situ during the foam manufacturing process).
Preferably the blowing agent gas should have a low vapor thermal
conductivity (VTC) so as to minimize conduction of heat through the
insulating foam. Thus, the vapor thermal conductivities for halocarbons
such as CFC-11, CFC-12 and hydrochlorodifluoromethane, CHClF.sub.2
(HCFC-22), at 25.degree. C. (i.e., 45.1, 55.7 and 65.9
Btu.multidot.ft.sup.-1 .multidot.hr.sup.-1 .multidot..degree.F..sup.-1
.times.10.sup.4) respectively) compare favorably to the VTC for air at
25.degree. C. (i.e., 150.5 Btu.multidot.ft.sup.-1 .multidot.hr.sup.-1
.multidot..degree.F..sup.-1 .times.10.sup.4). From these data, it can
readily be seen that the presence of a halocarbon blowing agent is
required for optimum thermal insulation properties with both thermoplastic
and thermoset foams.
A problem with hydrogen-containing alternative blowing agent HCFC-22 is its
rapid migration from thermoplastic foams. For example, in the case of one
grade of polystyrene, the permeation rate at 25.degree. C. for CFC-12 vs.
HCFC-22 was 4.2.times.10.sup.-9 g/hr vs. 6.5.times.10.sup.-8 g/hr (i.e.,
HCFC-22 diffused 15.5 times faster than CFC-12). Without some way to
prevent or slow down the rate of HCFC-22 permeation from polystyrene foam,
this blowing agent is unacceptable for producing good insulation foam,
using this particular grade of polystyrene.
HCFC-22 is also known to diffuse rapidly from some
polyurethane/polyisocyanurate foam formulations. Techniques for
slowing/preventing this blowing agent migration are required if the
halocarbon is to be useful in preparing these thermoset insulating foams.
In addition to the undesirable degradation of foam insulation value caused
by permeation losses of blowing agent, the effect of air entry from the
atmosphere into the foam cells is at least equally significant. As air
enters the foam cells, the vapor thermal conductivity of the cell gas
increases and the insulation value drops.
The blocking agents of this invention unexpectedly function to reduce air
entry into foams and/or to reduce the permeation of hydrogen-containing
blowing agents such as HCFC-22 from the foam cells, thereby producing more
effective/economical insulation foams.
For the purposes of the present invention, the term "blocking agent" is
used herein to denote hydrogen bond forming compounds which contain ether,
ester or ketone groups or the like. These hydrogen bond forming compounds
can bond or associate with hydrogen-containing halocarbon blowing agents
such as HCFC-22 and thereby reduce their rates of permeation from the
foam.
Unexpectedly, HCFC-22, difluoromethane (CH.sub.2 F.sub.2, HFC-32),
1,1,1-trifluoro-2,2-dichloroethane (CHCl.sub.2 CF.sub.3, HCFC-123),
1,1,2-trifluoro-1,2-dichloroethane (CHClFCClF.sub.2, HCFC-123a),
1,1,1,2-tetrafluoro-2-chloroethane (CHClFCF.sub.3, HCFC-124),
pentafluoroethane (CHF.sub.2 CF.sub.3, HFC-125), 1,1,2,2-tetrafluoroethane
(CHF.sub.2 CHF.sub.2, HFC-134), and 1,1,1,2-tetrafluoroethane (CH.sub.2
FCF.sub.3, HFC-134a) have been observed to associate or hydrogen bond with
compounds containing ether, ester or ketone groups. Glycols and other
polyhydroxy compounds tend to form intra- or inter-molecular hydrogen
bonds with themselves and thus do not associate strongly with HCFC-22.
HCFC-22, with hydrogen bonding esters, ketones or ethers, exhibits
dramatically reduced vapor pressure as a result of the association.
Furthermore, when these hydrogen bonding compounds are present in
thermoplastic polymers such as polystyrene, the permeation of HCFC-22 is
reduced/slowed as the result of the mutual association which occurs
between these compounds. The hydrogen bond forming agents additionally
function to improve the solubility of blowing agents such as HFC-134a in
thermoplastic polymers such as polystyrene.
Also, the mutual solubility of HCFC-22 and HCFC-123 or the like with
several hydrogen bond forming compounds further provides evidence of an
unexpected association between these materials. CFC-12 does not share this
unexpected solubility characteristic. Because of the solubility of many of
the hydrogen bond forming compounds in HCFC-22, these compounds are
suitable for dissolving in HCFC-22 and, thus, can be made commercially
available in this convenient form.
For purposes of the present invention and as previously mentioned, the
blocking agent can broadly be any compound that contains either an ether,
ester or ketone group or combinations of the same and is capable of
hydrogen bonding or the equivalent strong association or complexing with
hydrogen-containing halocarbons. For example, but not by way of
limitation, the following table lists examples of ether, ester or ketone
groups containing compounds which associate or hydrogen bond with
hydrogen-containing halocarbons such as HCFC-22.
HYDROGEN BONDING AGENTS
(1) Polyethylene oxide polymers
(2) Ethylene oxide/propylene oxide copolymers
(3) Polypropylene oxide polymers
(4) Polyethylene glycol mono- and dioleates
(5) Polyethylene glycol monostearates
(6) Alkylphenoxy polyethoxy ethanols
(7) Polyethylene oxide sorbitan monostearates and tristearates
(8) Polyethylene oxide fatty acid amides
(9) Primary and secondary alcohol ethoxylates
(10) Glyme, diglyme, triglyme and tetraglyme
(11) Mono-, di- and tripropylene glycol methyl ethers and ether acetates
(12) Dimethyl adipate, succinate and glutarate
(13) Ethylene oxide/propylene oxide adducts with a sucrose
(14) Ketones and polyketone polymers.
The use of hydrogen-containing blowing agents such as HCFC-22 with ether,
ester or ketone hydrogen bond forming compounds in polymer foams does not
preclude the simultaneous incorporation of blowing agents such as
1,1-dichloro-1-fluoroethane (CCl.sub.2 FCH.sub.3, HCFC-141b),
1-chloro-1,1-difluoroethane (CClF.sub.2 CH.sub.3, HCFC-142b),
1,1,1-trifluoroethane (CF.sub.3 CH.sub.3, HFC-143a), 1,2-difluoroethane
(CH.sub.2 FCH.sub.2 F, HFC-152), and 1,1,-difluoroethane (CHF.sub.2
CH.sub.3, HFC-152a) which do not tend to form strong hydrogen bonds. It
should be further appreciated that various CFCs may also be present as a
component of a blowing agent mixture useful according to the present
invention and that the present invention is applicable when CO.sub.2,
hydrocarbons or methyl formate are components of the blowing agent gas.
Similarly, various additives such as stabilizers, dyes, fillers, and the
like can be present in the blowing agent.
In addition to reducing the entry of air into and/or the migration of
hydrogen-containing blowing agents such as HCFC-22 from thermoplastic
foams, the hydrogen bond forming agents may provide other functions to the
foam manufacturing process. For example, compounds such as the
polyethylene oxide polymers may provide lubricity and thereby increase the
extrusion throughput or production rate. Furthermore, these compounds are
contemplated as potentially useful as polymer plasticizers and may
contribute advantageously to other properties.
The hydrogen bond forming agents of this invention are suitable for use
with thermoplastics such as polystyrene, polyethylene, polypropylene,
polyvinyl chloride, and the like to prevent loss of hydrogen-containing
blowing agents; however, they can also be used with thermoset polymer
foams such as polyurethane, polyisocyanurate, and phenolic resin foams.
Since these hydrogen bond forming agents associate with blowing agents
such as HCFC-22, they will function to reduce/prevent permeation of the
blowing agent in any compatible polymer foam system. Furthermore, these
hydrogen bond forming agents will function in the presence of other
additives normally used in polymer foams, such as stabilizers, dyes,
fillers, and the like.
The blowing agent concentration used to prepare most conventional
thermoplastic and thermoset polymer foams is generally in the range of
about 5 weight percent to about 30 weight percent (based on total weight
of the foam). To reduce migration of hydrogen-containing blowing agents
such as HCFC-22, the effective use concentration of hydrogen bond forming
agent is at least about 0.1 weight percent and preferably from about 1.0
to 20 weight percent (based on total formulation weight), most preferably
about 0.5 weight percent to about 10 weight percent. Typically, the
improved polymer foaming composition will contain from 1 to 100 parts by
weight hydrogen bond forming blocking agent for every 100 parts of
hydrogen-containing halocarbon blowing agent.
The actual method by which the blocking agent according to the present
invention is to be incorporated into the closed cell foam can vary
according to the specific application and composition being employed. In
the broadest sense, the blocking agent can be treated as any other foam
additive as generally known in the art. As previously stated, the blocking
agent in certain applications imparts beneficial effects to the polymer
phase in addition to reducing permeability and in such cases the blocking
agent can be added to the polymer. Since the blocking agent is
categorically a hydrogen bond forming compound, it may be advantageously
added to the blowing agent or preblended into the polymer (e.g.,
polystyrene) prior to extrusion or other method of fabrication. In the
case of thermoset foams (e.g., polyurethane/polyisocyanurate foams) the
hydrogen bond forming agents can be added to the foam in the isocyanate
(A-side) or the polyol (B-side) or added with the blowing agent at the
mixing head where the A-side and B-side are combined (i.e.,
third-streamed). For purposes of the present invention the term "A-side"
is used to specify the isocyanate containing component of a conventional
two component precursor foam system. The term "B-side" is used to specify
the polyol containing component. It should be appreciated that this
nomenclature may be reversed particularly in certain European literature.
It should be further appreciated that these precursor components to foams
typically contain other ingredients, additives, agents, diluent and the
like all as generally known in the art. Thus for example, but not by way
of limitation, the B-side will typically contain, in addition to the
polyol, a surfactant, a catalyst and one or more blowing agents. If the
hydrogen bond forming agent used contains free hydroxyl groups, this must
be taken into account when calculating the hydroxyl equivalent for the
B-side system. In the case where the blocking agent is preferentially more
soluble in one of the foam components, it is preferably added to that
component. For example, addition of the blocking agent to the polyol
component of two-component thermoset resin is preferred. Of course, the
addition to more than one component or either component is also
contemplated. In the case of phenolic foams, the hydrogen bond forming
agents can be added to the foam by preblending into the resole or added
separately at the mixing head prior to the foam laydown. The most
preferred method of adding the blocking agent is to mix it with the
blowing agent and as such the admixture of HCFC or HFC and blocking agent
is contemplated as being a commercially attractive product, per se. Again,
since the blocking agent is categorically a hydrogen bond forming
compound, in the case of the thermoset foams (e.g.,
polyurethane/polyisocyanurate foams) not only can a polyol be added as the
blocking agent but the polyol (B-side) can be viewed as the blocking
agent. Thus, as previously stated if the hydrogen bond forming agent used
contains free hydroxyl groups they must be taken into account when
calculating the hydroxyl equivalent for the B-side system. Conversely, the
ether and ester groups of the polyol found in the B-side should also be
view as contributing as the hydrogen bond forming blocking agent. As such,
in cases where there are ether and/or ester groups present in the polyol,
the polyol should be considered as a blocking agent.
The following examples are presented to further illustrate specific
critical properties of various specific embodiments of the present
invention, including vapor pressure, boiling point and permeation data, as
well as similar properties, for comparison purposes, of systems and
compositions outside the scope of the invention.
EXAMPLE 1
The solubilities of several representative hydrogen bond forming agents in
HCFC-22 were determined for 10 wt. % solutions at ambient temperature
(approximately 70.degree. F.). The solutions were prepared by combining
the hydrogen bond forming agents with HCFC-22 in 4 oz. plastic-coated
pressure bottles. Solubility was determined by visual examination. Table I
lists ten hydrogen bond forming compounds which are soluble to >10 wt. %
in HCFC-22. These hydrogen bond forming agents are soluble in HCFC-22,
HCFC-123 and HCFC-123a because of their bonding or association; whereas,
they are generally insoluble in CFC-12. The hydrogen bond forming agents
are also soluble in HCFC-141b.
Table I
Hydrogen Bonding Agent Solubility HCFC-22
The following hydrogen bonding agents are soluble at ambient temperature in
HCFC-22 to >10 wt. %.:
Hydrogen Bonding Agents*
"PLURONIC" F-108
"CARBOWAX" 3350
"WITCONOL" H35A
"TRITON" X-67
Polypropylene Glycol 2025
"ETHOFAT" 0/20
"ETHOMID" HT/60
"TERGITOL" 15-S-20
"ETHOX" DO-9
"TERGITOL" NP-40
* Solubilities determined at ambient temperature (approximately. 70.degree.
F.). Similar solubilities have been observed for HCFC-123, HCFC-123a, and
HCFC-141b even though HCFC-141b is not a strong hydrogen bond forming
HCFC.
EXAMPLE 2
Vapor pressure data were obtained for mixtures of CFC-12 and HCFC-22,
respectively, with hydrogen bonding agents. In these tests, 30 grams of
blowing agent was combined with 70 grams of hydrogen bond forming agent in
a 4 oz. plastic-coated pressure bottles. After thermostatting the bottles
at 70.degree. F., the vapor pressures were determined using a pressure
gauge accurate to 0.1 psi. Although HCFC-22 by itself has considerably
higher vapor pressure at 70.degree. F. than CFC-12 (121.4 psig vs. 70.2
psig), the formation of hydrogen bonds between the hydrogen bond forming
agents and HCFC-22 resulted in dramatic vapor pressure depressions to
values much lower than for CFC-12. The vapor pressure data are summarized
in Table II.
Boiling point data were obtained for a 30/70 blend of HCFC-123/DBE. The
data in Table IIA show an elevation in boiling point (relative to the
value calculated from Raoult's Law) of 17.degree. C. as the result of the
association or hydrogen bonding which occurs between these materials.
Similar boiling point elevations were observed for 30/70 blends of
HCFC-123/DPM and HCFC-123/DPMA.
Table IIB shows vapor pressure data for HFC-32, HCFC-124, HFC-125, HFC-134
and HFC-134a with DBE, acetone, and 2-pentanone. Each hydrogen bond
forming agent depresses the vapor pressure of the blowing agents.
TABLE II
______________________________________
Effect of Hydrogen Bonding Agents
on Vapor Pressure of HCFC-22
Blowing Vapor Pressure
Agent at 70.degree. F., psig
Bonding Agent Wt. % CFC-12 HCFC-22
______________________________________
None 100.0 70.2 121.4
"CARBOWAX" 3350
30.0 70.2 57.2
"PLURONIC" F-108
30.0 70.2 55.5
"WITCONOL" H35A
15.0 44.0 20.0
30.0 70.2 38.0(*)
"TRITON" X-67 15.0 70.2 29.5
30.0 70.2 41.0
"TWEEN" 61 30.0 70.2 70.5
Polypropylene Glycol
30.0 49.2(*) 39.3(*)
2025
"ETHOFAT" 0/20
30.0 57.5(*) 35.0(*)
"ETHOMID" HT/60
15.0 70.2 18.5
30.0 70.2 29.0
"CARBOWAX" 8000
30.0 70.2 61.0
Polyethylene Glycol
30.0 70.2 55.2
Cpd 20M
"POLYOX" WSRN-10
30.0 70.2 56.5
"TERGITOL" 15-S-20
15.0 70.2 15.0
30.0 70.2 26.5(*)
"TERGITOL" 24-L-92
30.0 59.2(*) 31.0(*)
"TERGITOL" NP-40
30.0 70.2 44.0
Polypropylene Glycol
30.0 54.0(*) 37.0(*)
425 (112.5 at (93.0 at
130.degree. F.)
130.degree. F.)
"PLURACOL" 975
15.0 46.0(*) 17.0(*)
(110.0 at (49.0 at
130.degree. F.)
130.degree. F.)
30.0 70.2 50.5(*)
(2 phases)
"ETHOX" DO-9 30.0 53.7(*) 39.5(*)
Diglyme 30.0 26.0(*) 7.0(*)
Glyme 30.0 16.0 2.5(*)
DBE 30.0 45.0(*) 21.5(*)
"ARCOSOLV" PM 30.0 35.0(*) 19.5(*)
Acetone 30.0 19.5(*) 5.9(*)
2-Pentanone 30.0 40.5(*) 14.5(*)
Polymethylvinyl Ketone
30.0 61.0(*) 45.5(*)
______________________________________
(*)solution
TABLE IIA
______________________________________
Boiling Point Elevation Data
Boiling Point, .degree.C.
Compound Actual Raoult's Law
______________________________________
HCFC-123* 27.6 --
DBE 196 --
30/70 HCFC-123*/DBE
81 64
DPM 188 --
30/70 HCFC-123*/DPM
88 67
DPMA 200 --
30/70 HCFC-123*/DPMA
93 60
______________________________________
*Commercial grade; typically including up to about 10 percent HCFC123a.
TABLE IIB
______________________________________
Effect of Hydrogen Bonding Agents
on Vapor Pressures of
HCFC-124, HFC-125, HFC-134, HFC-134a and HFC-32
Blowing
Blowing Agent Vapor Pressures
Bonding Agent
Agent Wt. % at 70.degree. F., psig
______________________________________
None CFC-114 100.0 12.9
DBE CFC-114 30.0 12.7(*)
None HCFC-124 100.0 34.1
DBE HCFC-124 30.0 1.2(*)
Acetone HCFC-124 30.0 0(*)
2-Pentanone
HCFC-124 30.0 1.8(*)
None HFC-125 100.0 163.8
DBE HFC-125 30.0 35.0(*)
Acetone HFC-125 30.0 10.0(*)
None HFC-134a 100.0 81.3
DBE HFC-134a 30.0 15.3(*)
Acetone HFC-134a 30.0 3.5(*)
2-Pentanone
HFC-134a 30.0 12.0(*)
None HFC-134 100.0 60.2
DBE HFC-134 30.0 7.0(*)
Acetone HFC-134 30.0 0(*)
None HFC-32 100.0 206.3
Acetone HFC-32 30.0 41.0(*)
______________________________________
(*)solution
EXAMPLE 3
For comparison purposes, HCFC-22 was combined with non-hydrogen bonding
agents, such as stearyl stearamide ("KEMAMIDE" S-180) and glycerol
monostearate ("WITCONOL" MST), and the vapor pressure of HCFC-22 showed
slight, if any, depression. Thus, compounds which form strong hydrogen
bonds with themselves, e.g., glycerol monostearate, do not associate with
HCFC-22 and do not reduce the measured vapor pressure. The vapor pressure
data are shown in Table III.
TABLE III
______________________________________
Vapor Pressure for HCFC-22
with Non-Hydrogen Bonding Agents
Blowing
Vapor Pressure
Agent at 70.degree. F., psig
Additive Wt. % CFC-12 HCFC-22
______________________________________
None 100.0 70.2 121.4
"KEMAMIDE" S-180
30.0 70.2 121.4
"WITCONOL" MST 30.0 70.2 118.0
"ALKAMIDE" HTDE
30.0 70.2 105.0
"ARMID" O 30.0 70.2 118.0
"SPAN" 60 30.0 70.2 108.5
Glycerin 30.0 70.2 121.4
"SELAR" OH 3007
30.0 70.2 121.4
"SELAR" PA 7426
30.0 70.2 121.4
"SURLYN" 8396-2
30.0 70.2 121.4
Polyacrylonitrile A-7
30.0 70.2 120.8
"SOLEF" 1008-1001
30.0 70.2 121.4
"ELVANOL" 90-50
30.0 70.2 121.4
______________________________________
EXAMPLE 4
The permeation of nitrogen and HCFC-22 through polystyrene film was
measured for polymer films with and without blocking agents.
The permeation data was obtained on 15-20 mil thick polystyrene films which
were prepared as follows:
(a) Hydrogen bond forming agents and polystyrene were passed through a twin
screw extruder three times at 400.degree. F. to ensure good blending of
components. The extruder used was a 28 mm Werner and Pfleider, Stuttgart,
Model 20S-K-28 twin screw.
(b) After pelletizing the extruded polymer, 15-20 mil thick films (in
6".times.6" sheets) were pressed at about 35,000 psig pressure using a
Barber-Coleman press.
(c) The 6".times.6" sheets of 15-20 mil film were cut into 47 mm diameter
circles or discs with a polymer die punch.
Permeation tests were run on polystyrene films containing various blocking
agents to determine the permeation of air and blowing agents in
polystyrene foam. Such film closely simulates polystyrene foam cell walls
and the permeation data are predictive of foam blowing agent retention and
susceptibility to air intrusion. Studies were made with HCFC-22 and
nitrogen (simulating air).
Polystyrene Film Preparation
(A) Mixing Polystyrene/Additives by Extrusion
Samples of polystyrene (2500 grams) plus blocking agents were hand mixed
and passed through a screw extruder three times at about 400.degree. F.
Three passes were used to ensure uniform blending of components. Since the
polymer mixes were extruded into a water tank for cooling prior to
pelletizing (between the passes through the extruder and after the third
extrusion), the pelletized samples were dried about 16 hours in a vacuum
oven at 175.degree.-200.degree. F. The extruder used was a 28 mm Werner
and Pfleider, Stuttgart, Model 20S-K-28 twin screw.
(B) Film Pressing of Polystyrene/Additive Mixtures
Using a Barber-Coleman press, 30 gram samples of polystyrene/additive mixes
(as pellets) were pressed into 6".times.6" sheets of film with 15-20 mil
thickness. The pressing was done at 400.degree. F. and at a pressure of
about 35,000 psig (maintained for 5 minutes).
(C) Film Discs for permeation Tests
Discs (15-20 mil thickness) were cut from 6".times.6" sheets of film. Five
discs of 47 mm diameter were made from each sheet. The discs were cut or
stamped at ambient temperature using a die punch made of A-2 type steel
(hardened).
Permeation Test Procedure
The permeation tests on the polystyrene film containing blocking agents
were conducted by a modification of ASTM D1434-82, "Standard Method for
Determining Gas Permeability Characteristics of Plastic Film and
Sheeting". This modified procedure is described in the Master of Chemical
Engineering Thesis, P. S. Mukherjee, Widener University, Chester, Pa.,
February 1988, entitled "A Study of the Diffusion and Permeation
Characteristics of Fluorocarbons Through Polymer Films".
Test Conditions
(1) All tests were run at a 20 psia pressure differential between the high
pressure side and the low pressure side of the permeation cell.
(2) Permeation tests were run at 60.degree. to 120.degree. C., with tests
for each blocking agent/polystyrene/gas combination being run at two or
more temperatures. Data for other temperatures were calculate from the
equation:
##EQU1##
where P is permeation coefficient, T is .degree.K. (.degree.C.+273.2) and
A and B are constants determined from the permeation coefficients
calculated from the following equation:
##EQU2##
(3) The permeation rates are based on a 1 cm.sup.2 by 1 cm thick film with
a 1.0 psia pressure drop across the film.
The permeation rate and permeation coefficient data for nitrogen in
polystyrene containing blocking agents are summarized in Table IV. Data
for HCFC-22 in polystyrene containing blocking agents are shown in Table
V. The units for permeation rate are g/hr and for permeation coefficient
are cm.sup.3 (STP).multidot.cm/sec.multidot.cm.sup.2 .multidot.cmHg. The
data summarized in Tables IV and V are calculated at 25.degree. C. from
data measured at other temperatures.
TABLE IV
__________________________________________________________________________
Permeation Data
Polymer: Polystyrene* Temperature: 25.degree. C.
Wt. %
Permeation Coeff.
Permeation
% Change In
Blocking in cm.sup.3 gas at STP cm
Rate Permeation
Gas Agent Polymer
sec cm.sup.2 (cm Hg)
g/hr Rate
__________________________________________________________________________
Nitrogen
None -- 8.00 .times. 10.sup.-11
1.86 .times. 10.sup.-9
--
Nitrogen
"WITCONOL"
5.0 5.50 .times. 10.sup.-11
1.28 .times. 10.sup.-9
-31.2
H35A
Nitrogen
"TRITON" X-67
5.0 4.49 .times. 10.sup.-11
1.04 .times. 10.sup.-9
-44.1
Nitrogen
Polypropylene
5.0 4.72 .times. 10.sup.-11
1.10 .times. 10.sup.-9
-40.9
Glycol 2025
Nitrogen
"TWEEN" 61
5.0 4.672 .times. 10.sup.-11
1.07 .times. 10.sup.-9
-42.5
__________________________________________________________________________
*"DYLENE" 8 polystyrene (Melt Index 6-7), Arco Chemical Company.
TABLE V
__________________________________________________________________________
Permeation Data
Polymer: Polystyrene* Temperature: 25.degree. C.
Permeation
Wt. %
Coefficient
Permeation
% Change In
Blocking
in cm.sup.3 gas at STP cm
Rate Permeation
Gas Agent Polymer
sec cm.sup.2 (cm Hg)
g/hr Rate
__________________________________________________________________________
HCFC-22
None -- 5.41 .times. 10.sup.-12
3.89 .times. 10.sup.-10
--
HCFC-22
"WITCONOL"
5.0 2.21 .times. 10.sup.-12
1.58 .times. 10.sup.-10
-59.4
H35A
__________________________________________________________________________
*"DYLENE" 8 polystyrene (Melt Index 6-7), Arco Chemcial Company.
EAMPLE 5
In a manner analogous to Example 2, vapor pressure data were obtained for
mixtures of HCFC-22 in polyols and for a mixture of HFC-134a in a polyol.
The vapor pressure data are summarized in Table VI.
TABLE VI
______________________________________
Effect of Polyols as
Hydrogen Bonding Agents
on Vapor Pressure
of HCFC-22 and HFC-134a
Blowing Vapor Pressure
Agent at 70.degree. F., psig
______________________________________
RAOULT'S
Hydrogen Wt. % FOUND LAW
Hydrogen Bonding
HCFC-22*
______________________________________
STEPANPOL PS-2502
2.9 0 15.2
5.4 13.5 27.7
7.8 17.0 37.0
17.9 43.5 64.5
20.6 64.0 68.0
PLURACOL P-410
2.0 0 11.0
4.0 0 20.6
6.0 3.0 29.0
8.0 6.5 36.3
10.0 9.0 42.9
12.0 10.6 48.9
PLURACOL TP-440
2.1 4.3 11.6
4.0 7.8 20.6
6.4 12.0 30.5
9.9 18.5 42.6
12.0 24.2 48.9
PLURACOL 1016 1.8 0.8 7.3
4.0 4.8 15.3
6.0 8.0 22.0
8.2 15.0 28.7
10.1 17.0 33.2
12.1 20.5 39.2
______________________________________
RAOULT'S
Blocking Agent
Wt. % FOUND LAW
Bonding Agent HFC-134A*
______________________________________
PLURACOL PT-440
2.5 0 6.8
5.0 4.0 12.7
7.6 12.0 18.1
10.0 19.0 22.4
______________________________________
*wt % blowing agent in hydrogen bonding agent
EXAMPLE 6
To further verify the differences in behavior between the conventional
chlorofluorocarbon blowing agents and the hydrogen-containing halocarbons,
the solubility of HCFC-134a was compared to that of CFC-12. The CFC-12 was
found to be miscible at 25.degree. C. in 150 SUS (32cs at 100.degree. F.)
oils including paraffinic oils, naphthenic oils, alkylated benzene oils
and PAG* oils. In contrast, the HFC-134a was found to be insoluble (<1 wt.
percent) in the paraffinic oils, naphthenic oils and alkylated benzene
oils. However, HFC-134a was found to be miscible in PAG oils at 25.degree.
C.
* UCON oils (n-butyl alcohol+propylene oxide or EO/PO)
EXAMPLE 7
Closed cell polyurethane thermoset foams were produced using CFC-11,
HCFC-22 and HFC-134a as the primary blowing agent and CO.sub.2 produced in
situ by addition of water. The K-factor for the respective foams were
measured and compared to vapor thermal conductivity data corresponding to
the blowing agents. The respective recipe for both the A-side and the
B-side components and the resulting data are presented in Table VII along
with the vapor thermal conductivity data.
TABLE VII
__________________________________________________________________________
Foams co-blown with water:
__________________________________________________________________________
A-Side 270 gms PAPI 580
B-Side 100 gms STEPAPNOL PS-2502
2.3 gms DC 193
5 gms HEXCEM 977
.35 gms POLYCAT 8
2.5 gms water
(see below) halocarbon
Foam Index** 250
Blowing B-Side Volume of gas
K-factor*
__________________________________________________________________________
Agent vap. pres.
MOLES Density age in days @ R
type gms
psig
B.A.
CO.sub.2
total
lbs/ft.sup.3
5 6
__________________________________________________________________________
CFC-11
12 0 0.09
0.14 0.23
3.42
0.171
CFC-11
22 0 0.16
0.14 0.30
3.24
0.162
CFC-11
32.6
0 0.24
0.14 0.38
3.31
0.151
HCFC-22
12 33 0.14
0.14 0.28
2.96
0.162
HFC-134a
12 28 0.12
0.14 0.26
2.97 0.172
__________________________________________________________________________
Foams blown without water:
__________________________________________________________________________
A-Side 158 gms PAPI 580
B-Side 100 gms STEPANPOL PS-2502
1.7 gms DC 193
1.35 gms HEXCEM 977
.17 gms POLYCAT 8
0.0 gms water
(see below) halocarbon
Foam Index** 250
Blowing B-Side Volume of gas
K-factor*
__________________________________________________________________________
Agent
vap. pres.
MOLES Density age in days @ R
type gms
psig
B.A.
CO.sub.2
total
lbs/ft.sup.3
10
__________________________________________________________________________
CFC-11
41 0 0.30
0.00 0.30
2.5 0.143
HCFC-22
26 0 0.30
0.00 0.30
2.8 0.162
__________________________________________________________________________
VAPOR THERMAL CONDUCTIVITY DATA
VTC, Btu/hr .multidot. ft .multidot. .degree.F.
BLOWING AGENT 25.degree. C.
60.degree. C.
__________________________________________________________________________
CFC-11 0.00451
0.00530
CFC-22 0.00660
0.00748
HFC-134a 0.00838
0.01020
CO.sub.2 0.00953
0.01107
__________________________________________________________________________
*(Btu .multidot. in/hr .multidot. ft.sup.2 .multidot. .degree.F.)
**(equivalents of isocyanate/equivalents of hydroxyl) .times. 100
The primary property of halocarbon blowing agents in insulating foam is to
provide good thermal insulation by virtue of their low vapor thermal
conductivity in the foam cells. By comparing the accompanying vapor
thermal conductivity data (VTC) for CFC-11, and HFC-134a or CFC-22, it is
apparent that conductivity of HFC-134a and CFC-22 is almost twice that of
CFC-11. Thus it is to be expected that an insulating foam made with
HFC-134a or CFC-22 would be a much poorer insulator than a foam made with
CFC-11. On the contrary and as seen in the k-factor data, the insulation
performance for the HFC-134a/CO.sub.2 and CFC-22/CO.sub.2 foam is
unexpectedly and essentially the same as that for the CFC-11/CO.sub.2
foam, wherein the HCFC-134a/CO.sub.2 and CFC-22/CO.sub.2 foam produced in
the presence of the blocking agent exhibited extremely fine closed cell
structure.
The chemicals used in the previous Examples and tests are identified
structurally and by source as follows:
__________________________________________________________________________
Designation Structure Source
__________________________________________________________________________
"CARBOWAX" 3350
Polyethylene
Union Carbide Corp.
glycol
"CARBOWAX" 8000
Polyethylene
Union Carbide Corp.
glycol
"Pluronic" F-108
Ethylene BASF Wyandotte Corp.
oxide/propylene
oxide copolymer
"WITCONOL" H35A
Polyethylene
Witco Corp.
glycol (400)
stearate
"WITCONOL" MST
Glycerol Witco Corp.
monostearate
"TRITON" X-67 Alkylpoly- Rohm and Haas Co.
ethoxy ethanol
"TWEEN" 61 POE (4) ICI Americas, Inc.
sorbitan stearate
Polypropylene Polypropylene
Union Carbide Corp.
Glycol 2025 glycol
"ETHOFAT" 0/20
Polyethylene
Akzo Chemie America
oxide oleate
"ETHOMID" HT/60
Polyethylene
Akzo Chemie America
oxide fatty
acid amide
Polyethylene Polyethylene
Union Carbide Corp.
Glycol Cpd 20M
glycol
"POLYOX" WSRN-10
Polyethylene
Union Carbide Corp.
oxide
"TERGITOL" 15-S-20
Linear Union Carbide Corp.
alcohol/ethylene
oxide
"TERGITOL" 24-L-92
Linear Union Carbide Corp.
alcohol/ethylene
oxide
"TERGITOL" NP-40
Nonylphenol/
Union Carbide Corp.
ethylene oxide
Polypropylene Polypropylene
Union Carbide Corp.
Glycol 425 glycol
"PLURACOL" 975
Sucrose BASF Wyandotte Corp.
polyol
"PLURACOL" P-410
Polypropylene
BASF Wyandotte Corp.
glycol
"PLURACOL" P-440
Trifunctional
BASF Wyandotte Corp.
polyol based
upon Polypropylene
glycol
"PLURACOL" 1016
Trifunctional
BASF Wyandotte Corp.
amino polyol
"STEPANPOL"PS-2502
Difunctional
Stepan Company
polyol based
upon Phthalic
anhydride
"PAPI" 580 Methylene DOW Chemicals
diisocyanate
"DC" 193 Silicone DOW Chemicals
surfactant
"HEXCEM" 977 Potassium Mooney Chemcials
octanoate
"POLYCAT" 8 N,N-dimethyl-
Air Products and
cyclohexyamine
Chemicals, Inc.
"ETHOX" DO-9 Polyethylene
Ethox Chemicals Inc.
glycol dioleate
Glyme Ethylene Aldrich Chemical Co.
glycol di-
methylether
Diglyme 2-Methoxy- Aldrich Chemical Co.
ethyl ether
DBE Mixture of Du Pont Co.
dimethyl adipate,
dimethyl gluta-
rate and di-
methyl succinate*
"ARCOSOLV" PM Propylene Arco Chemcial Co.
glycol mono-
ethyl ether
"ARCOSOLV" DPM
Dipropylene
Arco Chemical Co.
glycol mono-
methyl ether
"ARCOSOLV" DPMA
Dipropylene
Arco Chemical Co.
glycol mono-
methyl ether
acetate
"KEMAMIDE" S-180
Stearyl Witco Corp.
stearamide
Acetone -- Fisher Scientific
2-Pentanone Methyl Pfaltz and Bauer, Inc.
propyl ketone
"ALKAMIDE" HTDE
stearic Alkaril Chemicals, Ltd
diethanolamide
"ARMID" O Oleamide Akzo Chemie America
"SPAN" 60 Sorbitan ICI Americas, Inc.
stearate
Glycerin -- Aldrich Chemical Co.
"SELAR" OH 3007
Ethylene/ Du Pont Co.
vinyl alcohol
copolymer
"SELAR" PA 7426
Amorphous Du Pont Co.
nylon
"SURLYN" 8396-2
Ethylene/ Du Pont Co.
methacrylic
acid copolymer
Polymeric Acrylonitrile/
Du Pont Co.
Acrylonitrile A-7
methyl acrylate
copolymer
"SOLEF" 1008-1001
Polyvinyli-
Soltex Polymer Corp.
dene fluoride
"ELVANOL" 90-50
Polyvinyl Du Pont Co.
alcohol
"DYLENE" 8 Polystyrene
Arco Chemical Co.
Polymethylvinyl
-- Monomer-Polymer
Ketone (8919) Laboratories, Inc.
CFC-12 Dichlorodifluoro-
Du Pont Co.
methane
CFC-114 1,2-dichlorotetra-
Du Pont Co.
fluoroethane
HCFC-22 Chlorodifluoro-
Du Pont Co.
methane
HCFC-123 1,1,1-trifluoro-2,2-
Du Pont Co.
dichloroethane
HCFC-123a 1,1,2-trifluoro-1,2-
Du Pont Co.
dichloroethane
HCFC-124 1,1,1,2-tetrafluoro-
Du Pont Co.
chloroethane
HFC-125 Pentafluoroethane
Du Pont Co.
HFC-32 Difluoromethane
Du Pont Co.
HFC-134 1,1,2,2-tetrafluoro-
Du Pont Co.
ethane
HFC-134a 1,1,1,2-tetrafluoro-
Du Pont Co.
ethane
HCFC-141b 1-fluoro-1,1-di-
Du Pont Co.
chloroethane
__________________________________________________________________________
*17/66/16.5 mixture of esters
Having thus described and exemplified the invention with a certain degree
of specificity, it should be appreciated that the following claims are not
to be so limited but are to be afforded a scope commensurate with the
wording of each element of the claims and equivalents thereof.
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